Saeety-catch eor elevator



J. E. MITCHELL.

SAFETY CATCH FOR ELEVATORS. APPLICATION FILED AUG, 6. I918.

1,316,498. Patented e t. 16,1919.

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2a in .I. E. MITCHELL.

SAFETY CATCH FOR ELEVATORS.

APPLICATION FILED AUG. 6. ms.

Patented Sept. 16,1919.

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UNITED WN 1 orrica.

JOHN E. ivrrrcnnnn, or srmnenr-nnn TOWNSHIP, smyimrr-oonmYfion ro.

s r -G ms essemmas Sp c t n f lIiettersiPat m I L919.

pp at fi ed Aus '6, 9 8, f eri l m. M8529- case that the lifting cableof the elevator is.

broken or'suddenly loosened. I Afurther'objeet of the invention is toprovide a simple and effective device for this purpose which may beapplied to practically any .elevator and which will insure against theunintentional descent thereof. p

With the foregoing and other, objects in view, the invention consists inthe novel construction, combination and arrangement of partsconstituting the invention 'tobe hereinafter specifically described andillustrated in the accompanyingdrawings which form a part hereof whereinis shown the preferred embodiment of "the invention,ybut it is to-beunderstood that changes, variations and modifications can be resortedtowhich come within the scope of the matter hereinafter claimed.

In the drawings in which similar reference numerals indicate like partsin the different figures,

Figure 1 is a vertical sectional view taken approximately on line 1 ofFig. 3.

Fig. 2 is a sectional view taken approximately on line 2 of Fig. 1, and

Fig. 3 is a sectional view taken approximately on line 3 of Fig. 1.

The fixed portion of the elevator comprises the usual frame comprisingupright posts 1 arranged at the corners of an imaginary rectilinearfigure and stiffened and reinforced by means of cross bars 2 in theusual manner. As a part of the frame of the elevator shaft are a pair ofguides 3 oppositely disposed in the usual manner and preferably composedof wood. The guides and frame are of the usual construction and furtherdescription thereof is believed to be unnecessary. For brevity ofdescription the movable part of the elevator will be designated as acageand it embodies a lower platform 4 rovided with cutaway portions ornotches to receive the guides 3. Above the pla e 4 is hea .5prefe ablymaform in shape .and provided with notches 6 'to receive the guldes 3toprevents dewise movement of theentire cage dur ng itsvertical movement.The platform ftis supported from the head- 5 by means ofa pair of par,-

allel rods positioned'closely adjacentjto the ,g uides 3 and connectedibo'thlwith the head Sand with the platform 4:. The platform 4 isfurthermore connected with the headfby means of braces 8 which .pass upwardly over the upper }face of the head '5 and are :held in position bymeans of clips orholding members 9. Secured to each .of the upright bars7 "by means o-fclamps 10 are horizontal ,bars'll the outer ends of eachof which are provided with'bearings 12 the bearing at oneend of each barbeing 0-ppositely disposed to the corresponding bearing of the other barand in these pairs of bearings are mounted parallel shafts Secured tothe faces of the, head :5fare brackets 14; the lower ends o f whic hiare pro vided with bearings for. the shafts 13 so as to support themintermec liatelyio f the bear;v ings on the ends of the bars 11. Mountedon both .ends of both shafts @1 3 are toothed -wheels 15 each of whichis provided with a cutaway or flat portion 16 unprovided with teeth andthese portions are normally adapted to be out of contact with the guides3 when in their inoperative positions. Each toothed wheel is oppositelydisposed and on opposite sides from thetoothed wheel on the other shaft.These toothed wheels are so arranged that when rotated the teeth willengage or dig into the wooden guides 3 and prevent downward movement ofthe cage.

In order to insure the interengagement of the toothed wheels 15 with thesides of the guides 3 there is mounted on each of the shafts 13preferably centrally thereof an arm 17'each bearing at its outer end acounterweight 18. These arms 17 are capable of a vertical rockingmovement in unison with the rotation of the shafts 13 and in ordertolimit this movement there is provided at each side of the head 5 aplate 19 provided with a slot 2-0 through which slots the rms 17 extend,the outer ends of the slots being closed by portions 21 which form stepsor abutments for limiting the downward movement of the arms 1.7 and thecounterweights 18. The arms 17 are drawn downwardly to their inoperativeposition by means of coiled springs 22 extending beti'veen anchorages onthe arms 17 and the portions 21 of the plates 20. The central portion ofthe head 5 is provided with an anchorage 23 for a chain or otherflexible member 2 1 which terminates in a ring 25 to which is connecteda lifting cable 26, by means of which the cage is lifted. The ring 25 isconnected with each of the arms 17 by means of flexible connections suchas chains 27 which are united preferably with the outer portions of thearms near the coimterweights 18 and are designed to raise the arms 17upwardly to bring the toothed wheels 15 to their inoperative positionwhen the cable 26 is taut as clearly shown in Fig. 1. In case of a breakin the lifting cable 26 or a sudden slackening thereof thecounterweights swing outwardly and downwardly on their pivots, theshafts 13, and rotate the latter causing the teeth of the wheels 15 toengage the sides of the guides 3 and set up a gripping action forarresting further descent of the cage. The downward movement of the arms17 due to a slackening or breaking of the lifting cable 26 is aided bythe coiled springs 22 so as to cause as far as possible. aninstantaneous movement downwardly of the arms 17 to rotate the wheels 15to throw the teeth of the wheels 15 into quick contact and lookingposition with respect to the guides 3.

I claim:

The combination in an elevator of a pair of guides, a cage adapted toslide thereon, said cage embodying a cross head, a shaft mounted on eachside of said cross head at a point spaced downwardly thereof, an armmounted on each of said shafts and arranged when oscillated to partiallyrotate the former, a lifting cable connected centrally of said crosshead, chains connecting said lifting cable with the outer portions ofsaid arms and arranged to move said arms to their upper inoperativeposition when said cable is in a taut condition and synchronize with theupward movement of said cable, a toothed wheel mounted on each end ofeach of said shafts arranged when rotated in unison with its supportingshaft to establish gripping engagement with one of said guides forholding said cage against downward movement, a portion of each of saidtoothed wheels being unprovided with teeth and having a fiat portionarranged to lie parallel to and slightly removed from the face of aguide during the inoperative or upper position of said arms, an anchorfixed to each side of said cross head and extending lat-erally therefromwith an unsupported outer end and having a slotted opening therein eX-tending from the cross head to a point adjacent the outer end thereofand through which the adjacent arm extends at all times for limitedmovement, and a spring extending between the free outer end of eachanchor and the adjacent arm for normally moving the arm to its loweredinoperative position.

In testimony whereof I have hereunto set my hand.

JOHN E. MITCHELL.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. (3.

